1. No category

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In-class worksheet
Chem 226,Long
Structures, Formal Charges
Lewis Structures
Draw in the bonds and unshared electrons to complete each of the following Lewis structures. All are
neutral compounds.
H H
H :oe
HrOiH
H H
Itadlll:elTbo H*C-C-N*H
H-9*C---O--+I
I / 'oo
I
I
HHHHH
ethanol
acetamide
H-C*N-N-O,
| " !.
(ethanamide;
I "- l*
H={-o-P0----6-s
t "' I "
4'\
I
I\
methylnitrosoamine
:b:
t/
h
I
fu
dimethylphosphate
Hit
O
il
t
Usual Bondins for H. C. N. O with 0, *1. and -1 Formal Charses t4 + c'i-o-?-u
o^e**raloar>*'hur,4"
i+ l' A
charge...
la4,'
neutral bf,,z,",-l
il#'*#ffi-A.
|
H-H
'/
t+
d-tncl-
H:
H+
CH+
4 gsTadi
*cH*
: NH3
3 battd.t t- t .&nzpi-c
*NHo
Icx=
: NHz
!
o
H-O+t
,l
boolE t-J /a*a,palu
H-r+{
:kH
a
H
Formal Charge
Prob 2. The formal charges are shown on
the following partial structure of DNA.
Draw all the lone pairs. (A, T, G, and C are
abbreviations so don't do those)
Prob.La*. Identify the formal charge of any atom that does
not have azero formal charge in each of the following
structures. (all unshared electron pairs are shown)
b. What is the overall charse on each formula? rf,
Atl are 3ero, a4-cQt-t B r.a - t
HL
-+
\l
,J
C =l-l
HA
.
=N
c
r
).
H
* ;i-'
H3C:-N.
D
C=O
HF
.:-l:
+
:
. .u'q-:
l.o.:
G
?BX
rr=U.
..
)*
*trura{. a4r9,)*/*(mostlyfrom
or,zraU c.lrazgra-
H
:
f,l-O:
H, IH
'tlrn ;tLln af
0 adl
'i{cp-; I
l
'
!
"
on $nline collection of questions by William Reusch at Michigan State University. This
site also has many other good problems.
Go to: hnp://www2.chemistry.msu.edu/faculty/reuschlVirtTxtJml/Questionslproblems.htm
Arransemgnt of electron nairs around an atom (VSEPR)
Look at the central atom in each of the structures
Br
of directions that electro:
pairs come out from the an atom in H-C:N
the compound including lone pairs
a. Number
H-C:O
H
H-II-H H-9_H
I
Br-C
I
Il
I
H
(steric number)
b. Approximate bond angle(s)
formed between the different
directions of those electron pairs
+J,
c
-1
/6?"5"..-
i&o "
t3D"
4
l0c/,5
D
@ee*U,f
/of)J
))
/ 0?5.L
(arfa.aZ04
t
os"/
Bond-Line (Skeletal) and Other Condensed Structures
Drawing condensed structures:
HH:GHHHHHHH
H.--l
I I .. il I I I I
I I
-?
-e.-"-'=n-?-T-"-? -?-i-?-?:"-?-?-'
'-o.J-q,l-]
H/'
,o
n
I
:,J,.,i;,
I
*5j)i
cHr^-6*rq\c- c*/,-^t{} -cfrr-u); ca; ul; lll=cta- ff,-c&
&s
It t ' *"'1"'*'a
-*-^tt-**)
a
'Lv(lond:lina')
e
Ho-on*h
-r*a^-x
AW
'vrr
goa'L t'l"te -' t
*o)J
on--L*rrt
^'^'L;aLt'/"'e
:f;a{lff"
?
cholesterol
methylcyclohexane Ho-L
J*l
I
H"
4
How many rl's?
How many
c's? {7
How many
tl,s? 16
Converting condensed to bond-line structures
Sometimes acyclic structures are written all in one line to save space and be easier to type. For each of
the one-line condensed structural formulas below, draw
1) a condensed structure that is not all in one line
2) a bond-line structure
a.
(CHr)NCHzCH:CHz
oilf | -erlr-&l =42
I
\N..*-Z
I
b.
cH3(cHz)zcH(cH:)co2H
CA,Cll"
.) I Ul"Aj+C:0H
-l
ll
o
cl'
-^*;'
c. CH:CHCICHCICOCHzCN
oer#*?-fr-w,-c=r\i
C( UoQ A
S^/
Karen Long Fall2013